docs: Fix markdown syntax error and add DeepWiki badge for consistency

[wo-o29]

Description

This PR fixes a markdown syntax error in the English README and adds the DeepWiki badge to the Korean README for consistency across both documentation files.

• Fixes markdown formatting issue in section heading
• Ensures both language versions have consistent badge display
• Improves documentation accessibility by adding DeepWiki link to Korean version

Changes

• README.md: Removed trailing asterisks (**) from "Problems with Traditional Overlay Management" section heading
• README-ko_kr.md: Added DeepWiki badge [![Ask DeepWiki](https://deepwiki.com/badge.svg)](https://deepwiki.com/toss/overlay-kit) to header section to match English version

Motivation and Context

The English README had a markdown syntax error where the section heading "Problems with Traditional Overlay Management" had trailing asterisks that broke the proper heading format.

Additionally, the Korean README was missing the DeepWiki badge that exists in the English version, creating inconsistency between the two documentation files.

These changes ensure:

1. Proper markdown rendering of section headings
2. Consistent badge display across both language versions
3. Korean-speaking users can also access DeepWiki documentation

How Has This Been Tested?

• Verified markdown syntax renders correctly by previewing the README files
• Confirmed DeepWiki badge link works and points to the correct repository
• Checked that both README files now have matching badge sections in their headers

Screenshots (if appropriate):

Edit markdown syntax

Before	After

Add Deepwiki link

Before	After

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have performed a self-review of my own code.
• My code is commented, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• Any dependent changes have been merged and published in downstream modules.

[changeset-bot]

⚠️ No Changeset found

Latest commit: b1ea5fb

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.85%. Comparing base (6a96688) to head (b1ea5fb).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #211   +/-   ##
=======================================
  Coverage   99.85%   99.85%           
=======================================
  Files          15       15           
  Lines        1340     1340           
  Branches      262      262           
=======================================
  Hits         1338     1338           
  Misses          2        2           

Components	Coverage Δ
overlay-kit	99.85% <ø> (ø)

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